Snap switch



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SNAP SWITCH Filed Jan. 20, 1948 2 Sheets-Sheet 1 lmmww ri 25 195 F. com@ 2,505,505

' SNAP SWITCH Filed Jan. 20, 1948 2 Sheehs-Shee't 2 y l l f 1m Ewan. i (Vier/9.9 (ba/re Patented Apr. 25, 1950 UNITED STATES PATENT OFFICE' SNAP SWITCH Charles F. Coake, Indianapolis, Ind. Application January 20, 1948, Serial No. 3,322

(Cl. 20o-67) 4 Claims.

,her of parts.

Another object is to provide a novel and improved reed construction for a switch of the above type.

Another object is to provide an integral reed and actuating spring for use in a switch of the above type.

Various other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

In accordance with the present invention, the actuating spring is made integral with the reed and is designed to produce a toggle action which causes the actuating spring to snap from one position to the other when the end of the spring is shifted past its central balanced position. The switch may be single acting or double acting depending upon the range of movement permitted.

In one embodiment the actuating spring is stamped out of the reed in the form of a central tongue which is coiled about the free end of the reed with its free end brought into engagement with an abutment on the actuating arm. The spring is held under compression by the actuating arm and is shifted thereby from one side to the other of its central or balanced position for obtaining the snap action.

Although the novel features which are characteristic of this invention are pointed out more particularly in the claims, the nature of the invention will be better understood by referring to the following description taken in connection with the accompanying cic embodiments thereof have been set forth for purposes of illustration.

in the drawings:

Fig. 1 is a side elevation the present invention, section:

Fig. 2 is a view similar to Fig. 1 showing the switch in open contact position;

Fig. 3 is a top plan view of the switch of Figs. l and 2 with the cover removed;

Fig. i is detail view the reed blank;.

Fig. 5 is a side elevation similar to Fig. 1 showing a further embodiment of the invention;

Fig. 6 is a detail view of the reed shown in Fig. 5;

of a switch embodying drawings in which certain spe.

Fig. 7 is a side elevation similar to Fig. 1 showing a still further embodiment of the invention;

Fig. 8 is a detail view o1 the reed shown in Fig. 7; and

Fig. 9 is a plan view of the reed blank.

Referring to the drawings more in detail, the switch is shown'in Figs. l to 4 as comprising a housing I 0 and a cover suitable insulating material and are adopted to enclose a switch chamber I 2.

The reed, as shown in Fig. 4, comprises a stamping formed with side arms I1, end flanges 20 and 2i, and a central tongue I8 which extends from the end flange 20 toward the end flange 2l. A short tongue 22 projects from the end flange 2i to provide space for a hole 23. The ange 2i of the reed is attached to a boss i6 formed in the housing I0 by a screw I5 passing through the hole 23.

The actuating spring is formed by rst bending the end flange 20 upwardly to form a vertical flange as shown in Fig: 1 and thence curling the tongue I8 around the end flange 20 with its free end 25 extendng toward the end flange 2i and engaging an abutment 26 on a movable actuating arm 2'I which is shown in the form of a leaf spring having a fixed end 28 secured to the boss I6 by the screw I5 and having an S-shaped bend at its free end forming the abutment 26. A plunger 29 slidably mounted in the cover I I engages the actuating arm 21 at a point spaced from the fixed end 28 thereof by an amount dependent upon the leverage desired and the amount oi throw of the plunger.

For making electrical contact with the reed the screw I5 engages a, metal ferrule 30 extending through the boss I6 and carrying an external contact screw 3i. A fixed contact 4U is carried by a pin M extending through a boss t2 in the housing i0 and carrying nuts 43 bywhich an external conductor 44 is attached. The movable contact 45 is carried by the actuating spring i8.

The actuating arm 21 is sufficiently resilient to retract the plunger 29 and to return to its upward position as shown in Fig. 1 when the preswith the housing shown in .sure on the plunger is released. The coiled spring It is so arranged that it is held under compression by the abutment 26 so that it tends to snap in one direction or the other as the end 25 is shifted by the abutment 26 past the central or balanced position. In the position shown in Fig. l, the free end 25 of the spring I 8 is located above its balanced position causing the spring I8 to snap downwardly and close the contact 45, the reed arm i1 also fiexing about its fixed end in response to the downward force supplied by the coiled spring I8.

As the actuating arm 21 is flexed downwardly by depressing the plunger 29, the free end 25 of the spring I8 is shifted downwardly past the i I which are formed of balanced position to the position shown in Fig. 2. whereupon an upward force is produced which causes the spring I8 to snap into its upper position, flexing the arms I1 of the reed and opening the contact 45. The contact 46 thus opens with a snap action and the extent of opening is inden pendent of the amount of movement of the plunger 29.

For a make and break switch, as shown. the actuating arm 21 is adapted to return to its original position when the pressure on the plunger 29 is released, thereby causing the contact 45 to again close with a snap action when the free end 25 of the spring I8 passes its central position. There is also a wiping action between the contacts 45 and 40 produced by the flexing of the spring I8.

The upward movement of the spring I8 is limited by a boss 46 formed on the cover Il. If desired a contact may be carried at this po.nt for forming a double throw switch. Likewise the throw may be made adjustable by the provision of an adjusting screw 41. If it is desired to provide a construction wherein the switch reed remans in either actuated position, the actuating arm 21 may be made of non-resilient material in which case a separate plunger may be used to restore the arm 21 when it is desired to reclose the contact 45.

Inasmuch as the action of the reed is dependent upon the characteristics of the arms I1 and spring I8, the unitary construction insures that these elements which are stamped out of the same blank will always have the same relative characteristics. Hence the reed may be made uniform in action without the necessity of carefully checking the reed arms against the springs as would be required if they were madeof separate elements. The cost of assembly of the switch is also decreased due to a reduction in the number of parts which would otherwise be required. The switch is accordingly well adapted to volume commercial production.v

Referring to Figs. 5 and 6, the construction is generally similar to that of Figs.\1 to 4 andthe corresponding parts have been given the same reference characters. In this embodiment, however, the spring I8a has been bent into an S- shape with its free end 25 engaging abutment 26 as before. The spring lila in this case does not extend around the end ange 20 of the reed, but extends between the arms I1 toward the xed end thereof. The same toggle action is obtained as in the form of the invention above described.

Referring to Figs. 7, 8 and 9 a composite reed, spring, and actuating arm are formed in a single stamping. In this embodiment the parts corresponding to those in Figs. 1 to 4 have also been given the same'reference characters. The tongue I8b in this instance, however, extends outwardly beyond the arms I1, as shown in Fig. 9, and the actuating arm 21h is formed integrally with the arms I1 of the reed and extends from the fixed end of the reed toward the free end thereof. The reed is assembled by bending the actuating arm 21h upwardly and then downwardly to form the abutment 28 as shown in Fig. 7 and by coiling the tongue I 8b around the end ange 20 of the reed with its free end 25 engaging the abutment 26 of the actuating arm 21h.

The operation of this form of the invention is also similar to that described abovethe spring I8b coacting with the actuating arm to ex the reed upwardly and downwardly when the free end 2l ot the spring Ilb is shifted past its central balanced position. This form has the further advantage of reducing the switch elements to a single part which may be stamped from a blank in the form shown in Fig. 9 and is adapted for use by merely flexing the elements into the form shown in Fig. 7.

The switch may be adapted for use as a thermostat by replacing the actuating arm 21 of Fig. 1 with a bimetallic thermostatic element which is adapted to flex in response to changes in temperature. l

Although certain specic embodiments of the invention have been shown for purposes of illustration, it is to be understood that various changea and adaptations may be made therein, as will be readily apparent to a person skilled in the art. The invention is only to be restricted in accordance with the scope of the following claims.

What is claimed is:

1. A snap switch comprising a spring reed having a fixed end and a free end, an actuating spring comprising a tongue formed integral with said reed and having one end xed to the free end of said reed said tongue being curled around the free end of said reed and having a free end extending toward the iixed end of said reed, a movable actuating arm having a fixed end mounted adjacent the fixed end of said reed and having a free end extending toward the free end of said reed, said actuating arm having an abutment engaging the free end of said tongue and arranged to hold the tongue fiexed and under compression so that a toggle action is obtained for shifting said actuating spring with a snap action as the free end of the actuating arm is shifted transversely of said reed past a balanced position.

2. A snap switch comprising a spring reed having a fixed end and a free end, an actuating spring comprising a tongue formed integral with said reed and having one end fixed to the free end of said reed and having a free end extending toward the fixed end of said reed, a movable actuating arm having a fixed end mounted adjacent the fixed end of said reed and having a free end extending toward the free end of said reed, said actuating arm having an abutment engaging the free end of said tongue and arranged to hold the tongue flexed and under compression so that a toggle action is obtained for shifting said actuating spring with a snap action as the free end of the actuating arm is shifted transversely of said reed past a balanced position, a movable contact.

carried by said tongue, a fixed contact cooperating therewith, and means making an electrical connection to said reed.

3. A snap switch as set forth in claim 2 in which said tongue is coiled around said last end ange.

4. A snap switch as set forth in claim 2 in which said tongue is bent into S shape and projects between said side arms toward said fixed end.

CHARLES F. COAKE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,374,986 Fetter May 1, 1945 2,395,698 Tiffany Feb. 26, 1946 '2,417,652 Kunzler Mar. 18, 1941 2,458,518 Kohl Jan. 11, 1949 

